How many pills do you reckon you'll take in your lifetime? The answer, assuming you're an average person with nothing particularly amiss, is about 14,000. Chances are some won't do you any good, and others won't do what they were originally intended to do. Viagra, for example, began life as a not-very-good angina medication called UK92480; Ritalin was once an ineffective anti-depressant, until doctors started to prescribe it for children with ADHD. Now university students take it as a "cognitive enhancer" to make them cleverer.

Horizon: Pill Poppers (BBC2) was an enlightening and often alarming look at the global pill industry, "an ongoing clinical trial in which we all take part". Much of the time, it turns out, pharmaceutical companies don't really know what effects a new pill has until they launch it. This isn't surprising when you see how they invent drugs. They start with a bank of two million unnamed chemical compounds; then they take a molecule of a particular disease and expose it to the two million chemicals one at at a time to see if anything happens. I should say this is an entirely automated process, in case you're worried about the work-life balance of lab employees. Out of the two million combinations, only a few of the test tubes will start fizzing. Fifteen years and a billion dollars later, you might just have a new licensed drug.

One can see this process in two ways: a) it's so expensive, slow and thankless that we're lucky anybody bothers; b) it's so expensive, slow and thankless that the only possible way to make money from it is to ensure that as many people as possible are prescribed your new drug, whether they need it or not.

In some cases, you may need to invent the disease for which your pill is the treatment. In other cases, you can bypass the outmoded notion of "disease" altogether. There is an idea within the medical profession that every man over 50 and every woman over 60 ought to be prescribed statins, which are known to lower cholesterol levels. Not for heart disease; rather to stop people with high cholesterol possibly getting heart disease at some point in the future. And the "normal" level of cholesterol they use is the average for a 25-year-old. By that measure, nearly everyone over 30 is a potential candidate for this drug. That's got to be worth a billion dollars of any giant pharmaceutical company's money.

Pill Poppers had two main illustrative features: members of the public offering personal testimonies about how many pills they take, and lots of close-ups of pretty, coloured pills. If the first showed how integral the pill is to modern life, the second reminded us just how seductive an object it is – it's no coincidence they look like sweets.

Our pill culture might even be fun, if it weren't for side-effects. Some pills have more side-effects than effects: most over-the-counter pain medications containing codeine, for example, contain too little codeine to ease pain, but enough to get you addicted. Statins cause muscle aches, cramps, forgetfulness and fatigue, and they're for people who haven't got anything wrong with them yet. Sometimes the side-effect – sudden, unwanted erectile function, say – becomes the effect; it's just a matter of rewriting the label.

Towards the end of the programme, the price we pay for our participation in this grand experiment was summed up nicely by one expert. "You show me a drug with no side-effects," he said, "I'll show you a drug without benefits. The difference between a drug and a poison is basically the dose."

Episode two of The Persuasionists (BBC2) did not reward the theory that this new sitcom needed time to bed in. It's set in an advertising agency and features a talented cast (Adam Buxton, Simon Farnaby, Daisy Haggard) you have probably seen being funny in other things, but if you laughed at this, I'd like to try a handful of whatever pills you're on. Actually, I did laugh once, when a character tried to encapsulate Australian culture with the words "Have you ever worn shorts to a funeral?" but, had I not been watching in a professional capacity, I would have switched over long before that point. It's hard to locate exactly what went wrong with this project, so I'm recording a verdict of death by misadventure.